T-1, a mitotic arrester, alters centrosome configurations in fertilized sea urchin eggs
✍ Scribed by Itoh, Tomohiko J. ;Schatten, Heide ;Schatten, Gerald ;Mazia, Daniel ;Kobayashi, Akio ;Sato, Hidemi
- Book ID
- 102804300
- Publisher
- John Wiley and Sons
- Year
- 1990
- Tongue
- English
- Weight
- 838 KB
- Volume
- 16
- Category
- Article
- ISSN
- 0886-1544
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✦ Synopsis
Abstract
T‐1 induces modifications in the shape of the centrosome at division in fertilized eggs of the North American sea urchin, Lytechinus pictus. Phase contrast microscopy observations of mitotic apparatus isolated from T‐1treated (1.7–8.5μM) eggs at first division shows that the centrosomes already begin to spread or to separate by prophase and that the mitotic spindle is barrel‐shaped. When eggs are fertilized with sperm that have been pretreated with T‐1, the centrosomes become flattened; the spindles are of normal length. Immunofluorescence microscopy using an anti‐centrosomal monoclonal antibody reveals that T‐l modifies the structure of the centrosome so that barrel‐shaped spindles with broad centrosomes are observed at metaphase, rather than the expected focused poles and fusiform spindle. Higher concentrations of T‐l induce fragmentation of centrosomes, causing abnormal accumulation of microtubules in polar regions. These results indicate that T‐l directly alters centrosomal configuration from a compact structure to a flattened or a spread structure. T‐l can be classified as a new category of mitotic drugs that may prove valuable in dissecting the molecular nature of centrosomes.